Just providing a pointer to the NifTools site. I have been playing around with NifSkope in order to "fix" some of the "issues" I am assuming exist in the Soul Gems Differ meshes. I noticed that they have some decent documentation, but it is a bit outdated.
We generally need to collect relevant info on modding tools and resources, so I thought we could create the threads with pointers under this forum category and begin to share knowledge about these tools and resources .. this might also help to formulate bridges among the disparate modding-related communities out there.
Standard release and documentation --> NifTools - NifSkope | PyFFI | NifLib
New Alpha release (recommended)